


A Knight of Faerghus

by SpicyMeerkatPasta (MxMearcstapa)



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: And he gets a couple, Bisexual Sylvain Jose Gautier, Exhibitionism, F/M, Female My Unit | Byleth, Fluff and Smut, Jealousy, M/M, Married Dimitri Alexandre Blaiddyd/My Unit | Byleth, Married Sex, Multi, Oral Sex, Plot What Plot/Porn Without Plot, Porn with Feelings, Post-Timeskip | War Phase (Fire Emblem: Three Houses), Sex, Smut, Sylvain Jose Gautier Needs A Hug, Threesome - F/M/M, Vaginal Sex, Voyeurism, dimileth, dimivain, sylveth
Language: English
Status: Completed
Published: 2020-12-18
Updated: 2020-12-18
Packaged: 2021-03-10 17:54:45
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,460
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28141221
Author URL: https://archiveofourown.org/users/MxMearcstapa/pseuds/SpicyMeerkatPasta
Summary: There is something shared between Byleth and Dimitri that Sylvain loathes to see, a gentleness that he worries he will never find. No one has ever looked at him the way Byleth and Dimitri look at each other, and it chafes him more than he likes to admit.Good thing he’s not here to be the soft one.Post time-skip, shortly after Byleth and Dimitri are married and Byleth is declared archbishop.Early for Dimileth Spring Fever~
Relationships: Dimitri Alexandre Blaiddyd/My Unit | Byleth, Dimitri Alexandre Blaiddyd/Sylvain Jose Gautier, Sylvain Jose Gautier/My Unit | Byleth
Comments: 14
Kudos: 105
Collections: Dimileth Spring Fever





	A Knight of Faerghus

**Author's Note:**

> *tosses a crumpled up piece of paper in your direction and hides behind a couch*  
> Unfolding the piece of paper reveals the following words:
> 
> "please don't tell my parents i wrote this"
> 
> This is my first smut, so please be gentle. ^_^''

The King of Faerghus likes to watch, and Sylvain, a loyal knight, likes to give him a show.

Shirtless, Sylvain slouches back in a wooden chair. Opposite him, Dimitri sits on the bed, similarly undressed. The King bites his lip, the tie of his pants already loosened. That he’s already so disrobed is a miracle within itself. When this arrangement first began, Dimitri had needed a great deal of coaxing, of reassurance. It had been Byleth’s idea—something to help the two of them “loosen up,” she’d suggested. Sylvain hadn’t expected anything past the initial encounter, but of late he found himself invited night after night to return to the royal chambers.

So despite his obvious nervousness, Sylvain knows Dimitri is eager for this. Eternally reticent, Dimitri is not yet sure that he should want it, that he deserves it, but when things begin to heat up, that reservation will drop as it always does. It is one of the many parts of the evenings Sylvain looks forward to.

The King just needs a little push.

Byleth slinks between them, the dark outline of her panties visible through her light slip. They used to start with her fully nude, but extra squirming they discovered Dimitri does as she’s undressed was too appetizing to ignore.

It begins, as always, with a soft kiss between the King and Queen. There is something shared between them that Sylvain loathes to see, a gentleness that he worries he will never find. No one has ever looked at him the way Byleth and Dimitri look at each other, and it chafes him more than he likes to admit.

Good thing he’s not here to be the soft one.

If there is something pure between the two of them, Sylvain enjoys the dark pleasure of muddying it when he puts his hands on Byleth. Tonight, their exchange leaves him feeling extra raw, so he stands, his hands on her hips, and spins Byleth to face him with a rough, sloppy kiss. Her sound of surprise melts into his mouth, and he swallows it with her kisses as her hands snake up through his hair. He likes kissing Byleth. She has always met him with the same intensity he gives, and tonight is no exception. Enthusiasm goes a long way in his book.

He spends a short time running a hand over her curves, enough to marvel why Dimitri would ever share such a beauty, and enough to savor that he does. Dimitri’s a fool not to keep her to himself, and Sylvain is content to let him be—he’s a fool himself for being here. He pulls back Byleth’s shift and drops it to the floor, then takes his seat and pats his lap with a grin. Byleth straddles him, eager to seal the gap between their lips. She’s hungry tonight, and that suits him well. It’ll make Dimitri hornier, watching her go wild, and it’s good material to beat off to later. With her breasts soft against his chest and her warmth against his groin, getting hard takes only moments. Sylvain turns his head, directing her down his neck, and peeks over her back at Dimitri.

Dimitri stares back intently, rubbing himself almost shyly through his pants. Sylvain can see his erection straining against the fabric and chuckles breathlessly. Silly Mitya. So easily worked up.

They haven’t even gotten to the fun part.

Sylvain could stay like this a while longer, reveling in Byleth’s hunger, but he’s eager to see Dimitri lose himself a little more. He eases Byleth off his lap and turns her around before pulling her down onto him again.

“Let’s give our king a little something to look at, hm?” he purrs into Byleth’s ear. She leans her head back and sighs as Sylvain’s lips trail down her neck. He steadies her on one knee, grips her waist with one hand, and kneads her breast with the other.

From the bed, Dimitri groans softly.

_That’s right, big guy. Look at her._

Dimitri’s finally freed himself from his trousers, hand sliding steadily up and down his girth, attention rapt on the scene in front of him. Sylvain hides his grin in the nape of Byleth’s neck and gives her breast a light squeeze. The touch elicits a small moan, and Dimitri echoes the sound. Sylvain throbs in response to them. He slides Byleth back to the center of his lap, and she spreads her legs so beautifully in response that Sylvain can’t help the buck of his hips. Not yet. He can’t get carried away yet.

He threads his arms back through Byleth’s and brushes her nipples lightly. Stiff as the first frost in autumn. Sylvain thrusts his hips again and pinches, and Byleth arches into him with a cry that makes Dimitri gasp and pitch forward. As he watches Dimitri’s pace increase, the head of his cock dark with pressure, Sylvain nearly loses his composure. He closes his eyes, blushing like a schoolboy. He’s got more experience than that, more self-control, and he’s not here for himself anyway. Not exactly. Not directly. Byleth’s hips are rocking on top of his, and he refocuses, moving in rhythm with her. With a furtive hand, he reaches to stroke the thin fabric of her panties. Drenched. Just as he expected.

“Take them off,” she gasps, and Sylvain obliges.

“Yours, too,” she says, and Sylvain twitches again. Some nights, it’s just Byleth squirming in his arms while Dimitri beats himself senseless. On the best nights, Sylvain gets to feel something other than his own hand around himself.

Looks like it’s going to be a good night then.

“As it pleases Your Grace,” he teases, stripping. Byleth is hard to read at the best of times, but there is no mistaking the hunger in her eyes tonight. With flushed lips, she says, “You’re too good to us, Sylvain.”

He has never heard her say such a thing before, and it sends a shiver across his skin.

“Just doing my best to serve king and country,” he jokes. “And the goddess, of course.”

Byleth actually smiles, and Sylvain’s grin drops. She is beautiful, and again he rues that she chose Dimitri. That Dimitri chose her. He’s been chasing them both longer than they have each other, and he has nothing to show for it.

Those thoughts dissolve as Byleth drops to her knees.

“Beloved, what are you doing?” Dimitri asks, but it’s no real protestation. He is still stroking himself, languid, lazy. He wants to see what happens next as much as Sylvain does.

“Loyalty is hard-earned,” the Queen, the Archbishop, Byleth says. She runs her fingers along the inside of Sylvain’s thigh, and he exhales forcefully. “It deserves a reward, wouldn’t you agree?”

Evidently Dimitri does, as a dark, longing sound rumbles out of him. Sylvain watches the King’s pace pick up again and licks his lips. Byleth leans forward and grips Sylvain at his base. She wraps her lips around his tip, and a grunt escapes him. Her mouth is hot and wet, and her tongue is not shy. His fingers curl into her hair, and he pushes himself in deeper despite knowing this is a gift. He will take it. He will take anything they give him, and they have to know it by now.

Byleth doesn’t protest; rather, she hums in amusement and pulls him a little deeper in yet. The velvet of her mouth is more than welcome, and his hips jerk a little faster.

Again, he rues Dimitri as he fucks Byleth’s mouth. Again, he’s grateful for the feeling of her lips. It’s not the best head he’s ever had, but it’s far from the worst, and there’s something extra special about watching Dimitri’s chest, sweaty and golden, heave as he watches them, pumping himself raw and red. Dimitri releases himself for a moment, lifting his hand to his mouth. He opens to lick his palm when Sylvain interjects.

“Allow me, Your Majesty,” he offers. Dimitri reddens somehow—Sylvain didn’t think he could get any redder—but tentatively extends his hand. Sylvain keeps the fingers of one hand entangled in Byleth’s hair and grabs Dimitri’s hand with his other.

He means to give Dimitri only a few solid swipes, but the King makes such a sound every time Sylvain’s tongue runs over his skin that he just can’t leave it at that. He slips three of Dimitri’s rough fingers—middle, pointer, and ring—past his lips and sucks. Dimitri groans, long and low, and Byleth draws Sylvain in even further to her mouth. His tip brushes the back of her throat, and Sylvain tugs at her hair, moaning into Dimitri’s hand. The King grabs hastily at himself with his other palm.

With a laugh, Sylvain spits him out and wipes the excess saliva from his lips. “Patience, your Majesty.”

Dimitri has no patience, ignoring the epithet and switching hands back to pump himself urgently. This is what Sylvain came to see. Dimitri’s vigor, his lust, his loss of control, one hand racing over his cock, the other cupping and squeezing his sack. He’s getting close.

Sylvain feels himself on the edge, too, and wonders. Will Fódlan’s new archbishop let him come in her mouth and swallow him whole, or will he get to spill his seed on her pretty face?

But then again, it’s been a better night than Sylvain could ever have hoped for, and he’s here to give the king a show. What will he be able to see if Byleth’s pretty face is turned away from him?

Though his body protests strongly, Sylvain pulls himself out past Byleth’s hungry lips, and goddess above (or below, on her knees, he supposes with a profane grin), she pouts at him.

“Dimitri’s close, Professor,” he says, the old title slipping out of him. He lifts her chin gently. “You should deal with him.”

This will be an easy night to finish alone, maybe even twice.

“Sylvain,” Byleth pants. The desire in her eyes is so strong that it shakes him. “I want you to fuck me.”

“ _What_ ,” he breathes, but Byleth rises and turns away, whispering something to Dimitri. The King stops a full beat, eye locked with his queen’s, and then his surprise crumbles into something needier, and he nods, resuming his pace.

Byleth smirks, triumphant, and kneels over Dimitri as he leans back. She tosses an expectant look back at Sylvain, and he freezes.

No way. Much as he’d relish acquainting himself with Byleth’s soft insides, no way Dimitri’s cool with it. Touching and grinding for the King’s amusement is one thing. This is another.

Dimitri lifts his head to look at Sylvain, strands of his hair clinging damply to his face. Softly, he says, “You’d keep Her Grace waiting?”

Sylvain moves before the rest of him can catch up. Before someone, _anyone_ , changes their mind. He grabs hold of Byleth’s ample waist and presses his length against her slit. Byleth purrs and pushes back, and Sylvain slides into her.

She’s tighter than he expected given that’s she regularly riding Dimitri. Much tighter. Sylvain pumps once, tentative, and Byleth moans, squeezing warm and wet around him. His hands clench around her waist.

“How does it feel, beloved?” Dimitri murmurs, cradling her palm in his cheek.

“Good,” Byleth breathes. “It feels so good.”

Sylvain’s hips jerk of their own accord, and he lets them find their rhythm. Byleth’s head drops down, and Sylvain hears her sounds of pleasure abate into Dimitri’s mouth.

Something beneath him grazes his thigh, rushing quickly, so light it tickles. Sylvain looks down. Dimitri’s knuckles, as he pleasures himself, are rubbing against Sylvain’s leg. He shifts forward slightly, pushing deeper into Byleth and closer to Dimitri. The King’s hand rests a moment—to touch Byleth’s dripping center, if her shudder is any indication—and Sylvain feels her tighten around him at the same time he feels the full length of the royal lance against his thigh, rigid and ready to burst.

Sylvain growls, gripping Byleth’s hips, and buries himself in her, hard and fast. She grunts with every thrust, and Dimitri grabs himself again and speeds, the motion so quick against Sylvain’s thigh it’s almost constant. Sylvain suspects a rash by the end of it, but the sounds Dimitri makes more than make up for it. A tightness coils sharply in Sylvain’s gut, twisting and compressing with every progressively higher-pitched cry from Byleth. Sylvain sees her back arch and Dimitri bend up with her, and he wonders if he’ll get to feel Dimitri spill over them both—and the tightness springs loose. He pulls out at the last moment, coming in spurts all over Byleth’s backside.

Quick as lightning, Dimitri grabs her hips and slams her down to the hilt. Byleth’s final cry is the most magnificent of all, and Sylvain watches thunderstruck as his come drips down her back, and the King and Queen of Faerghus come undone in each other’s arms.

A bitter wave of envy rises in him as their foreheads touch, gentle smiles warming their faces.

“You were beautiful, beloved.”

“So were you.”

Sylvain cannot resist breaking the moment, petty as it feels. After they have given him so much, it is still not enough, and he hates himself for it.

“Guess I’ll see you guys later,” he says. Winces.

Byleth and Dimitri give him puzzled looks. There’s a too-long pause, and the silence suffocates him. Sylvain bends to gather his clothing.

“Sylvain,” Dimitri calls. Sylvain turns away. As he pulls his pants back on, he hears the shuffle of sheets on the bed and feet on the floor.

He is surprised to feel warm hands take his.

“Sylvain,” Byleth says, and he turns to face them. She strokes his cheek with her knuckles, the kind of smile curving her lips that she saves for Dimitri. Sylvain looks warily at his king, his comrade, his…something. When he sees the same smile on Dimitri’s face directed towards him, he shakes.

“Sylvain, we care for you. Both of us.”

Byleth nods. “You’re a part of this. Of us.”

They kiss him gently, Byleth on his jaw and Dimitri on his brow. Something hot stings Sylvain’s eyes, and he takes a deep breath and looks at the floor. He can’t cry. He won’t. Even if he wants to. Even if he knows they’d let him.

“You guys are so serious,” he says, ignoring the tremor in his voice. He wipes his eyes and sniffs.

“Only when it matters,” Byleth says. “And you matter to us.”

“Augh—stop, or I actually _will_ cry.”

“Wouldn’t that be something to see,” Dimitri muses.

Sylvain laughs. “Don’t count on it, Your Majesty. This isn’t that kind of show.”

  
  



End file.
